Neurotoxic Effects of Neonicotinoids on Mammals: What Is There beyond the Activation of Nicotinic Acetylcholine Receptors?-A Systematic Review

Pollution and partitioning of neonicotinoid insecticides in free-grazing ducks and their eggs: Implications for human health

Neonicotinoid insecticides are used extensively in many pest control schemes across the globe; but little is known about their impacts on free-grazing domestic birds and the quality of meat or eggs produced from such birds. This study assessed the pollution and partitioning of neonicotinoids in serum and eggs of free-grazing ducks from 5 provinces of Thailand and elucidated the associated human health implications. Biological samples (duck serum, egg albumins, and egg yolks) and environmental samples (soil, water, feed) were collected from 9 duck farms in Thailand and subjected to LC/MS/MS analysis. Out of 6 neonicotinoid compounds targeted, five were detected in duck serum. Imidacloprid had the greatest median concentration of 1.4 ng/mL and the highest detection frequency (df) of 85.8 % in the ducks' serum, followed by acetamiprid (median concentration = 0.4 ng/mL; df = 2.8 %), clothianidin (median concentration = 0.2 ng/mL; df = 9.4 %) or thiamethoxam (median concentration = 0.2 ng/mL; df = 7.5 %) and dinotefuran (only one sample was contaminated with 6.3 ng/mL of dinotefuran). The neonicotinoids were similarly detected in soil, water, and feed samples obtained from the duck farms, suggesting that the ducks were exposed to the insecticides from the nearby agricultural fields. The neonicotinoid compounds selectively accumulated in the albumin of duck eggs compared to yolk. The median concentration ratios of albumin to yolk obtained for imidacloprid, dinotefuran, thiamethoxam, clothianidin, and acetamiprid were 694, 463, 458, 382, and 263, respectively. However, upon human health risk analysis, levels of neonicotinoids detected in duck eggs were not found to present any appreciable risks to duck egg consumers.

6-Chloronicotinic Acid Induces Toxicity in Mouse Neural Stem Cells via the C3ar1 Signaling

Neural stem cells (NSCs) are essential for brain development due to their ability to proliferate and differentiate into various neural cell types. Neonicotinoid insecticides (NNIs), which have replaced traditional pesticides, are now widely used and frequently detected in environmental and biological samples. Prenatal exposure to NNIs has been associated with an increased risk of neurodevelopmental disorders in offspring, yet the causal relationship and the underpinning mechanism remain to be clarified. As one of the primary metabolites of chloropyridinyl neonicotinoids, 6-chloronicotinic acid (6-ClNA) has been identified as a potential neurotoxin, though its effects on NSCs have not been fully explored. Here, we demonstrate that 6-ClNA exposure significantly disrupted NSC proliferation and differentiation in vitro. Transcriptomic analyses revealed that 6-ClNA altered the expression of pathways related to proliferation, apoptosis, and inflammation, with notable activation of the C3ar1/C1qa signaling axis. Genetic ablation of C3ar1 using siRNA markedly restored NSC proliferation and neurosphere formation, as well as reduced apoptosis, suggesting a central role of C3ar1/C1qa in mediating 6-ClNA's neurotoxic effects. These findings imply that early-life exposure to NNIs may affect the fitness and function of NSCs, wherein the C3ar1 pathway plays an indispensable role.

Insecticides and testicular health: mechanisms of injury and protective natural products

In agriculture and public health, insecticides are vital chemicals that help manage diseases and control pests. However, their extensive use has raised concerns about their negative consequences on both humans and animals. Pesticide exposure impacts numerous human organs, including the reproductive system. Infertility is caused by reproductive system disorders, which is why they have received a lot of attention in recent decades. According to what is currently known, insecticides are among the substances that may lower the quality of the semen produced by exposed workers. The mechanisms of this action are still unclear, even though numerous underlying mechanisms have been suggested. With an emphasis on the harmful effects of insecticides on male reproductive processes, this review provides a thorough analysis of the toxicity profile of these substances. To reduce insecticides' negative impacts on human and animal health and to direct future research initiatives, it is essential to comprehend their harmful consequences.

Neonicotinoid pesticides in African agriculture: What do we know and what should be the focus for future research?

This review provides a comprehensive overview of the direct and indirect effects of neonicotinoid pesticides (NEO-P) within African agricultural ecosystems and identifies research gaps, particularly in the monitoring and regulation of pesticide use. We observed a decline in the numbers of NEO-P studies conducted in Africa since 2019 with 40.7% of the countries reporting at least one study to date. Imidacloprid (33.5%), acetamiprid (23.3%), and thiamethoxam (25.0%) are the most reported NEO-P across the continent with concentrations range from 9.0 × 10-5 to 7.2 × 107 mg kg-1, 1.7 × 10-5 to 2.1 × 103 mg kg-1, and 1.0 × 10-5 to 4.7 × 104 mg kg-1, respectively. NEO-P have been reported in honey, water, vegetables, fruits, and staple foods in most countries and in 92-100% of human urine samples collected in Ghana and Cameroon. This widespread presence indicates a potential food safety and public health concern, warranting further study. Studies on NEO-P interactions with bees have emanated mainly from North Africa (35.3% published studies) while Central/Middle, and Southern Africa accounted for 11.8% each of these studies, all of which were conducted in Cameroon and South Africa, respectively. It is important to have contextual evidence to understand neonicotinoids-pollinator interactions across specific African regions and countries; however, literature regarding the extent of NEO-P toxicities/effects on pollinators is required in 44 African countries. The environmental persistence of NEO-P and their broad-spectrum impact necessitate a re-evaluation of current regulatory practices and adoption of more sustainable pest management strategies across the continent. Furthermore, future studies should focus on investigating the long-term exposure to NEO-P, advanced computational methods in ecological risk assessments and eco-friendly alternatives to NEO-P.

Use of agrochemicals resulted in anemia and inflammation among farmers in Fako Division, Cameroon

The use of agrochemicals as plant growth regulators, pesticides, and soil fertilizers can result in insults among farmers and other non-targeted organisms. The adverse effects of agrochemicals are of global concern, though limited studies have delineated their toxicity on blood cells and inflammatory parameters in Fako division in Cameroon. This study examined the impact of occupational exposure on haematological and inflammatory parameters among farmers in Fako division. Briefly, 165 farmers who occupationally applied agrochemicals and a reference population of 75 non-farmers were interviewed on types of agrochemicals used, knowledge and safety during use of agrochemicals, as well as related symptoms of exposure. Serum cholinesterase (acetylcholinesterase and butyrylcholinesterase) activities were measured as biomarkers of exposure to agrochemicals. Complete blood count and serum levels of interleukin-6 (IL-6) and nitric oxide (NO) were determined as haematological and inflammatory biomarkers. Results disclosed frequent use of insecticides, fungicides, herbicides and fertilizers with neglect of personal protective equipment. Reported symptoms of exposure to agrochemicals were consistent with decrease in cholinesterase activities. Exposure to agrochemicals decreased erythrocyte count and red cell distribution width, as well as increased mean cell volume, mean corpuscular hemoglobin, serum levels of NO and IL-6 in farmers; suggesting anemia and increased cellular inflammation. In conclusion, the use of agrochemicals resulted in inhibited cholinesterase activities, induced anemia, and promoted cell inflammation in farmers. These findings call for more sensitization and training of the farmers to minimize agrochemical exposure and related health hazards.

Residue determination and decline pattern of abamectin and fenpyroximate in okra fruits: a prelude to risk assessment

This study developed and validated an LC-MS/MS analytical method for determining abamectin and fenpyroximate residues in okra fruits. The method optimization focused on chromatographic separation and ionization conditions, adding formic acid and ammonium formate to enhance ionization efficiency and signal sensitivity. Validation was performed according to SANTE guidelines, demonstrating good selectivity, linearity (R 2 > 0.998), precision, recovery, and minimal matrix effects (14.6% for abamectin and 5.2% for fenpyroximate). The limit of detection (LOD) was set at 0.0006 mg kg-1 for abamectin and 0.0002 mg kg-1 for fenpyroximate, while the limit of quantification (LOQ) was 0.002 mg kg-1 and 0.001 mg kg-1, respectively. Precision was within acceptable limits, with intra-day RSD of 11.4% for abamectin and 7.6% for fenpyroximate. Recovery ranged from 84.2% to 98.6%, meeting the acceptable 70-120% range. Persistence studies indicated that abamectin and fenpyroximate residues dissipated over time, with half-lives of 2.3 and 2.45 days, respectively. The pre-harvest interval (PHI) required for residues to fall below the maximum residue limit (MRL) was estimated to be 2.6 days for abamectin and 6.9 days for fenpyroximate. The risk quotient was assessed based on the Egyptian adult consumers' consumption of okra, ensuring a negligible risk.

Embryonic exposure to valproic acid and neonicotinoid deteriorates the hyperpolarizing GABA shift and impairs long-term potentiation of excitatory transmission in the local circuit of intermediate medial mesopallium of chick telencephalon

Embryonic exposure to valproic acid and imidacloprid (a neonicotinoid insecticide) impairs filial imprinting in hatchlings, and the deteriorating effects of valproic acid are mitigated by post-hatch injection of bumetanide, a blocker of the chloride intruder Na-K-2Cl cotransporter 1. Here, we report that these exposures depolarized the reversal potential of local GABAergic transmission in the neurons of the intermediate medial mesopallium, the pallial region critical for imprinting. Furthermore, exposure increased field excitatory post-synaptic potentials in pre-tetanus recordings and impaired long-term potentiation (LTP) by low-frequency tetanic stimulation. Bath-applied bumetanide rescued the impaired LTP in the valproic acid slices, whereas VU0463271, a blocker of the chloride extruder KCC2, suppressed LTP in the control slices, suggesting that hyperpolarizing GABA action is necessary for the potentiation of excitatory synaptic transmission. Whereas a steep increase in the gene expression of KCC2 appeared compared to NKCC1 during the peri-hatch development, significant differences were not found between valproic acid and control post-hatch chicks in these genes. Instead, both valproic acid and imidacloprid downregulated several transcriptional regulators (FOS, NR4A1, and NR4A2) and upregulated the RNA component of signal recognition particles (RN7SL1). Despite different chemical actions, valproic acid and imidacloprid could cause common neuronal effects that lead to impaired imprinting.

Associations between neonicotinoids and inflammation in US adults using hematological indices: NHANES 2015-2016

Background

Toxicological studies suggest neonicotinoids increase oxidative stress and inflammation, but few epidemiological studies have explored these effects.

Methods

National Health and Nutrition Examination Survey (NHANES) 2015-2016 data were used to estimate associations between neonicotinoid exposure and inflammatory markers, including the C-reactive protein-to-lymphocyte count ratio (CLR), monocyte-to-high-density lipoprotein ratio (MHR), monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), derived NLR (dNLR), lymphocyte-to-monocyte ratio, platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) using linear and multinomial logistic regression models. Sex was evaluated as a potential modifier.

Results

Detection of any parent neonicotinoid (β = -0.62, 95% confidence interval [CI] = -0.98, -0.26) and imidacloprid (β = -0.48, 95% CI = -0.87, -0.10) was associated with decreased CLR. Clothianidin was linked to reduced MLR (β = -0.04, 95% CI = -0.07, -0.02), but increased lymphocyte-to-monocyte ratio (β = 0.52, 95% CI = 0.27, 0.77). Higher dNLR (β = 0.85; 95% CI = 0.26, 1.43) was noted with detection of any neonicotinoid metabolite. Moderately high PLR was observed with detection of any neonicotinoid metabolite (relative risk ratio [RRR] = 1.63, 95% CI = 1.27, 2.09) or 5-hydroxy-imidacloprid (RRR = 2.19, 95% CI = 1.40, 3.41). Sex-modified analyses showed positive associations in males and inverse associations in females for MHR (P int = 0.099, clothianidin), PLR (P int = 0.026, clothianidin), and SII (P int = 0.056, any parent neonicotinoid; P int = 0.002, clothianidin), while the opposite pattern was noted with CLR (P int = 0.073, any parent neonicotinoid) and NLR (P int = 0.084, clothianidin).

Conclusion

Neonicotinoids may be associated with inflammatory changes, with potential sexual dimorphism. Further studies are required to explore these findings.

Transcriptome analysis reveals the molecular mechanisms of neonicotinoid acetamiprid in Leydig cells

At present, the reproductive toxicology of neonicotinoids has received greater attention, however, its potential mechanisms are still not fully understood. Acetamiprid (ACE) is a new-generation neonicotinoid and has become a ubiquitous contaminant in the environment. This study aimed to investigate the toxic effects of ACE in TM3 Leydig cells based on transcriptome analysis. The viability and apoptosis of TM3 cells exposed to different concentrations of ACE were assessed by CCK8 and flow cytometry, respectively. After ACE exposure, transcriptome analysis was performed to screen differential expression genes (DEGs), followed by qPCR verification. Results showed that ACE exposure resulted in a time- and dose-dependent decrease in the viability of TM3 cells (p < .05). ACE also exerted a dose-dependent pro-apoptotic effect on TM3 cells. Results of RNA-seq showed that 1477 DEGs were obtained, of which 539 DEGs were up-regulated and 938 DEGs were down-regulated. GO and KEGG analyses of DEGs showed that DNA replication and cell cycle might be the key mechanisms for the cytotoxicity of ACE. qPCR results demonstrated that Mdm2, Cdkn1a (p21) and Gadd45 were significantly increased, and Pcna, Ccna2 (CycA), Ccnb1 (CycB), Ccne1 (CycE), and Cdk1 were significantly decreased, indicating that ACE exposure might promote G1/S and G2/M cell cycle arrest. Additionally, FoxO, p53, and HIF-1 signaling pathways and ferroptosis might play important roles in ACE-induced reproductive toxicity. Collectively, this study provides new perspectives into the mechanism of ACE-induced reproductive toxicity and lays a theoretical foundation for the in-depth study of non-target toxicity mechanisms of neonicotinoid insecticides.

Berberine chloride loaded nano-PEGylated liposomes attenuates imidacloprid-induced neurotoxicity by inhibiting NLRP3/Caspase-1/GSDMD-mediated pyroptosis

Concerns have been expressed about imidacloprid (IMI), one of the most often used pesticides, and its potential neurotoxicity to non-target organisms. Chronic neuroinflammation is central to the pathology of several neurodegenerative disorders. Hence, exploring the molecular mechanism by which IMI would trigger neuroinflammation is particularly important. This study examined the neurotoxic effects of oral administration of IMI (45 mg/kg/day for 30 days) and the potential neuroprotective effect of berberine (Ber) chloride loaded nano-PEGylated liposomes (Ber-Lip) (10 mg/kg, intravenously every other day for 30 days) using laboratory rat. The histopathological changes, anti-oxidant and oxidative stress markers (GSH, SOD, and MDA), proinflammatory cytokines (IL1β and TNF-α), microglia phenotype markers (CD86 and iNOS for M1; CD163 for M2), the canonical pyroptotic pathway markers (NLRP3, caspase-1, GSDMD, and IL-18) and Alzheimer's disease markers (Neprilysin and beta amyloid [Aβ] deposits) were assessed. Oral administration of IMI resulted in apparent cerebellar histopathological alterations, oxidative stress, predominance of M1 microglia phenotype, significantly upregulated NLRP3, caspase-1, GSDMD, IL-18 and Aβ deposits and significantly decreased Neprilysin expression. Berberine reduced the IMI-induced aberrations in the measured parameters and improved the IMI-induced histopathological and ultrastructure alterations brought on by IMI. This study highlights the IMI neurotoxic effect and its potential contribution to the development of Alzheimer's disease and displayed the neuroprotective effect of Ber-Lip.

Exploring the Effects of Imidacloprid on Liver Health and the Microbiome in Rats: A Comprehensive Study

The current study investigates the systemic effects of imidacloprid, one of the most widely used neonicotinoid insecticides, on the liver and gut microbiome of rats in detail. With consideration of recent discussions on the potential harmfulness of imidacloprid to environmental and human health, the aim was to investigate the influence of this compound in the framework of controlled exposure at different dosages, namely, IMI-5, IMI-10, and IMI-30. Histopathological examination showed that liver morphology changed significantly with the dose, including in terms of cellular disorganization and signs of stress, with an alteration in the hepatic architecture. Morphological changes were related to disturbances in the activity of liver enzymes, reflecting deteriorating liver function with increased imidacloprid exposure. In parallel with this, a deep analysis of the gut microbiome revealed dramatic changes in microbial diversity and composition. Alpha diversity, represented by the Chao1 and Shannon indices, was significantly reduced with an increased dosage of imidacloprid. Subsequent beta diversity analysis, as visualized by principal component analysis, showed distinct clustering among the microbial communities, separated well between control and imidacloprid-treated groups, especially at higher dosages. Taxonomic analysis revealed an increase in the Firmicutes/Bacteroidetes ratio and a change in key phyla including Actinobacteria, Bacteroidetes, and Verrucomicrobia. A heatmap and bar charts further confirmed dose-dependent changes in microbial abundance. These changes point toward imidacloprid-induced dysbiosis, a reduction in microbial diversity, and an imbalance in the F/B ratio, usually associated with metabolic disorders. Overall, given these findings, it would seem that imidacloprid does indeed impose serious negative impacts on both liver function and gut microbiota composition and may have further impacts on health and ecological safety.

Small volume solid phase extraction method for comprehensive analysis of neonicotinoids, their metabolites, and related pesticides in water

Neonicotinoid insecticides (NEOs) such as clothianidin, imidacloprid, and thiamethoxam are used worldwide. The occurrence of their degradates, for instance, clothianidin-n-desmethyl (CLO-N-DES), clothianidin-urea (CLOU), imidacloprid urea (IMIU) and olefin (IMIO), as well as thiamethoxam urea (THXU), have seldom been documented in water due to the lack of a sensitive analytical method. In this study, a method only requiring 12 mL of water sample was developed and validated to quantify 8 NEOs, 13 metabolites, and 3 related insecticides using solid phase extraction (SPE) coupled with HPLC-MS/MS. The method demonstrated good linearity (r2 > 0.99), with limits of detection (LOD) ranging from 0.16 to 1.21 ng/L and limits of quantification (LOQ) from 0.54 to 4.03 ng/L in water samples. Validation showed accuracy between 70 and 130 % and precision below 15 % for most analytes. The method's performance was comparable to, or better than, existing methods, with the advantage of requiring much smaller sample volumes. Using this method, we monitored the occurrence and seasonal variability of NEOs and their metabolites in various surface water and groundwaters matrices from across Iowa. For example, analysis of water samples from private wells across three Iowa counties detected several NEOs, with notable findings including the first detection of flupyradifurone (FLU) in Iowa well water. Surface water analysis from five locations revealed frequent detection of NEOs and their metabolites, with some concentrations exceeding U.S. EPA chronic toxicity benchmarks for freshwater invertebrates. In addition, this is the first study to demonstrate the occurrence of CLO-N-DES, CLOU, and THX-U in US surface water. The study helps advance analytical methods for NEOs and their metabolites while also highlighting their widespread occurrence in Iowa waters and associated ecological risks, emphasizing the need for more comprehensive monitoring of these compounds.

Effect of Insecticides Imidacloprid and Alpha-Cypermethrin on the Development of Pea (Pisum sativum L.) Nodules

Insecticides are used commonly in agricultural production to defend plants, including legumes, from insect pests. It is a known fact that insecticides can have a harmful effect on the legume-rhizobial symbiosis. In this study, the effects of systemic seed treatment insecticide Imidor Pro (imidacloprid) and foliar insecticide Faskord (alpha-cypermethrin) on the structural organization of pea (Pisum sativum L.) nodules and their transcriptomic activity were investigated. The plants were treated as recommended by the manufacturer (10 mg/mL for Imidor Pro and 50 µg/mL for Faskord) and twofold concentrations were used for both insecticides. Insecticides had no visible effect on the growth of pea plants. The nodules also showed no visible changes, except for the variant treated with twofold concentration of Imidor Pro. However, the dry weight of shoots and roots differed significantly in insecticide-treated plants compared to untreated plants in almost all treatments. The number of nodules decreased in variants with Imidor Pro treatment. At the ultrastructural level, both insecticides caused cell wall deformation, poly-β-hydroxybutyrate accumulation in bacteroids, expansion of the peribacteroid space in symbiosomes, and inclusions in vacuoles. Treatment with Faskord caused chromatin condensation in nucleus. Imidor Pro treatment caused hypertrophy of infection droplets by increasing the amount of matrix, as confirmed by immunofluorescence analysis of extensins. Transcriptome analysis revealed upregulation of expression of a number of extensin-like protein-coding genes in nodules after the Imidor Pro treatment. Overall, both insecticides caused some minor changes in the legume-rhizobial system when used at recommended doses, but Faskord, an enteric contact insecticide, has fewer negative effects on symbiotic nodules and legume plants; of these two insecticides, it is preferred in pea agricultural production.

Human acute poisoning incidents associated with neonicotinoid pesticides in the U.S. Incident Data System (IDS) database from 2018-2022 - frequency and severity show public health risks, regulatory failures

BACKGROUND

Neonicotinoid pesticides ('neonics') - imidacloprid, thiamethoxam, clothianidin, acetamiprid, dinotefuran-are the most widely used class of insecticides in the world. They have a neurotoxic mechanism of action, similar to nicotine. They are detected in food, waterways, tap water, and breast milk.

METHODS

We make use of the non-occupational human pesticide poisoning reports in the U.S. Environmental Protection Agency (EPA) online Incident Data System (IDS). The data set contains individual incidents, and incidents aggregated and submitted in bulk to EPA. IDS reports are predominantly self-reported information of varying and often low level of detail and are not routinely validated or verified by EPA.

RESULTS

We reviewed 842 non-occupational human poisoning incidents associated with neonics in the IDS from 2018 through 2022. There are four human fatality reports, two associated with clothianidin and two with acetamiprid. Major illnesses such as seizures were reported in several cases, including with dinotefuran cockroach bait product, and an imidacloprid lawn product. Moderate poisonings make up 88% of the total poisonings (740 of 842), with most of those associated with imidacloprid (547 incidents) or dinotefuran (102 incidents). Common reported symptoms classified as moderate often included two or more of the following: headaches; dizziness; lethargy; eye or throat irritation; skin itching and rash; chemical burns and skin peeling; face swelling; muscle weakness or tremors; vomiting; diarrhea; pain and tightness in chest; open sores; and general pain. These incidents stem mainly from residential uses, such as lawn and garden insect repellents, home pest treatments for bed bugs or roaches, and products used to treat pets for fleas and ticks.

CONCLUSION

Given the evidence of neurotoxicity, EPA should use its legal authority to cancel unsafe products and unnecessary uses - including from seed treatments, and residential pet and lawncare products - to prevent further human suffering.

Central nervous system disturbances by thiamethoxam in Japanese quail (Coturnix japonica): In vivo, ex vivo, and in silico study

The neurotoxic effects of neonicotinoids (NEOs) have been widely reported in relation to the poisoning of wild birds, yet the underlying molecular mechanism has remained elusive. This study employed Japanese quails (Coturnix japonica) and primary quail embryonic neurons as in vivo and ex vivo models, respectively, to investigate the neurotoxic effects and mechanism of thiamethoxam (TMX), a representative neonicotinoid insecticide, at environmentally relevant concentrations. Following a 28-day exposure to TMX, metabolomic analysis of quail brain revealed TMX-induced changes in glutamatergic, GABA-ergic, and dopaminergic function. Subsequent ex vivo and in silico experimentation revealed that the activation of nicotinic acetylcholine receptors and calcium signaling, induced by clothianidin (CLO), the primary metabolite of TMX, served as upstream events for the alterations in neurotransmitter synthesis, metabolism, release, and uptake. Our findings propose that the disruption of the central nervous system, caused by environmentally significant concentrations of NEOs, may account for the avian poisoning events induced by NEOs.

Prenatal exposure to neonicotinoid insecticides, fetal endocrine hormones and birth size: Findings from SMBCS

BACKGROUND

Neonicotinoid insecticides (NNIs) were reported to be endocrine disruptors and cause adverse health effects in human. However, epidemiological evidence about the effect of prenatal NNIs exposure on birth outcome and hormones remains limited.

OBJECTIVES

This study aimed to explore the effects of prenatal NNIs exposure on neonatal birth size and endocrine hormones, and assess the potential mediating role of hormones.

METHODS

The study included 860 mother-child pairs from the Sheyang Mini Birth Cohort Study. 12 parent NNIs (p-NNIs) and 6 metabolites of NNIs (m-NNIs) were measured in maternal urine samples collected on their delivery days, and 5 thyroid hormones and 2 sex hormones were analyzed in cord serum. The concentrations of p-NNIs and its specific metabolite(s) were summed to characterize the role of each class of NNIs. Generalized linear model and weighted quantile sum regression were used to examine the impact of prenatal NNIs exposure on birth size and endocrine hormones, and potential mediating roles of hormones were further explored using mediation analysis.

RESULTS

Higher detection frequencies of m-NNIs were observed than those in p-NNIs. A decrease in neonatal head circumference for gestation age z-score was associated with a 10-fold increase in 5-OH-IMI (β = -0.15, 95 %CI: -0.26, -0.03), ∑DIN (β = -0.22, 95 %CI: -0.40, -0.03), ∑IMI (β = -0.20, 95 %CI: -0.35, -0.06) and ∑NNIs (β = -0.23, 95 %CI: -0.42, -0.04). ∑IMI and ∑DIN were the major contributors to the significantly negative mixture effect and no sex-specific effect was observed. Negative associations were observed between ∑DIN and TT3 (β = -0.013, 95 %CI: -0.025, -0.002), ∑IMI and T (β = -0.035, 95 %CI: -0.065, -0.004), respectively. Furthermore, TT3 and T demonstrated 6.7 % and 6.1 % mediating effects on the negative association of prenatal ∑DIN and ∑IMI exposure with head circumference.

CONCLUSIONS

Our findings suggested the potential endocrine disruptive properties of NNIs and their impacts on head circumference. Endocrine hormones may partly mediate these associations.

Prenatal and childhood neonicotinoid exposure and neurodevelopment: A study in a young Taiwanese cohort

Neonicotinoid insecticides (NEOs) dominate the global pesticide market because of their low cost and effectiveness. However, epidemiological studies regarding the potential adverse health effects of exposure to NEOs before birth and in early childhood are limited. Therefore, this study investigated the associations between NEO exposure before birth and during early childhood and neurodevelopment. A total of 273 mother-child pairs were enrolled in this study. Mothers provided urine samples in the third trimester and breast milk during the first and third months of lactation. Their children provided urine samples and were evaluated for neurodevelopment by using the Bayley Scales of Infant and Toddler Development, Third Edition at 2-3 years (N = 96) and the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) at 4-6 years (N = 63). The sum of the concentrations of seven NEOs (ΣNEOs) and the relative potency factor of NEOs, based on comparison with imidacloprid (IMIRPF), were used to assess total exposure to NEOs. Multivariate linear regression analyses were conducted to assess the associations between prenatal and childhood exposure to NEOs and neurodevelopment. The results of the analysis revealed that clothianidin (CLO) and thiamethoxam were the most common NEOs to which children in the Taipei metropolitan area were exposed and that exposure concentrations were high in the Taipei metropolitan area. Imidacloprid was the most frequently detected NEO during the postnatal period. Additionally, exposure to NEOs through breast milk was low. Exposure to CLO, ΣNEOs, and IMIRPF in boys aged 4-6 years was negatively correlated with WPPSI-IV Fluid Reasoning Index. The results of this study indicate that exposure during the third trimester to NEOs does not affect neurodevelopment but that childhood exposure to NEOs may, especially for boys. Further studies with larger sample sizes are required to confirm the sex-specific associations between NEO exposure and neurodevelopment.

Cytotoxicity induced by three commercial neonicotinoid insecticide formulations in differentiated human neuroblastoma SH-SY5Y cells

Background

Neonicotinoid insecticides are used worldwide for crop protection. They act as agonists at postsynaptic nicotinic acetylcholine receptors (nAChRs), disrupting normal neurotransmission in target insects. Human exposure is high due to the widespread use of neonicotinoids and their residues in food. This study aimed to evaluate the in vitro neurotoxicity of three neonicotinoid commercial formulations Much 600 FS® (imidacloprid 600 g L-1), Evidence 700 WG® (imidacloprid 700 g kg-1), and Actara 250 WG® (thiamethoxam 250 g kg-1) in differentiated human neuroblastoma SH-SY5Y cell line.

Methods

Cells were incubated with the pesticides for 96 h, and the cytotoxicity was evaluated through the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium·bromide (MTT) reduction and neutral red (NR) uptake assays. Toxicological pathways such as reactive oxygen (ROS) and nitrogen species (RNS) production, mitochondrial membrane potential, cell death mode, and the expression of the pro-apoptotic protein Bax were also evaluated.

Results

EC50 values of 266.4, 4,175, and 653.2 mg L-1 were found for Much®, Evidence® and Actara®, respectively. Significant increases in ROS and RNS generation were observed for all pesticides, while mitochondrial membrane potential and Bax protein expression showed no significant changes. Analysis of cell death mode revealed an increase in early apoptotic cells.

Conclusion

Therefore, neonicotinoid insecticides are potentially neurotoxic, reinforcing concerns about human exposure to these commercial formulations.

Fluctuating Asymmetry Spotted Wing Drosophila (Diptera: Drosophilidae) Exposed to Sublethal Doses of Acetamiprid and Nicotine

Long-term exposure to low concentrations of toxic substances can cause several adverse consequences ranging from molecular to morphological. Sublethal doses may also lead to increased tolerance in the offspring of surviving individuals. One of the consequences of such stress is deviations from the ideal body symmetry during development, reflected by increased levels of fluctuating asymmetry (FA). This research aimed to verify FA in the wing veins of insects belonging to the Drosophilidae family-Drosophila suzukii, a fruit pest controlled by the insecticide acetamiprid, a neonicotinoid. To determine whether FA varied depending on insecticides present in the diet, multigenerational cultures of D. suzukii were carried out on media supplemented with different concentrations (below the LC50) of two insecticides. Nicotine was used as a positive control. Fecundity decreased, the number of insects decreased, and breeding did not continue beyond the tenth generation. However, the FA level at different concentrations was similar, and high FA values were observed even at lower acetamiprid concentrations. We did not see significant changes in FA levels in subsequent generations. D. suzukii proved extremely sensitive to acetamiprid, and FA is a good index of this sensitivity.

Effects of neonicotinoid residues on non-target soil animals: A case study of meta-analysis

Neonicotinoids (NEOs) are currently the fastest-growing and most widely used insecticide class worldwide. Increasing evidence suggests that long-term NEO residues in the environment have toxic effects on non-target soil animals. However, few studies have conducted surveys on the effects of NEOs on soil animals, and only few have focused on global systematic reviews or meta-analysis to quantify the effects of NEOs on soil animals. Here, we present a meta-analysis of 2940 observations from 113 field and laboratory studies that investigated the effects of NEOs (at concentrations of 0.001-78,600.000 mg/kg) on different soil animals across five indicators (i.e., survival, growth, behavior, reproduction, and biochemical biomarkers). Furthermore, we quantify the effects of NEOs on different species of soil animals. Results show that NEOs inhibit the survival, growth rate, behavior, and reproduction of soil animals, and alter biochemical biomarkers. Both the survival rate and longevity of individuals decreased by 100 % with NEO residues. The mean values of juvenile survival, cocoon number, and egg hatchability were reduced by 97 %, 100 %, and 84 %, respectively. Both individual and cocoon weights were reduced by 82 %, while the growth rate decreased by 88 % with NEO residues. Our meta-analysis confirms that NEOs pose significant negative impacts on soil animals.

Ecological impacts and management strategies of pesticide pollution on aquatic life and human beings

Pesticide contamination has become a global concern. Pesticides can sorb onto suspended particles and deposit into the sedimentary layers of aquatic environments, resulting in ecosystem degradation, pollution, and diseases. Pesticides impact the behavior of aquatic environments by contaminating organic matter in water, which serves as the primary food source for aquatic food webs. Pesticide residues can increase ammonium, nitrite, nitrate, and sulfate in aquatic systems; thus, threatening ecological environment and human health. Several physical, chemical, and biological methodologies have been implemented to effectively remove pesticide traces from aquatic environments. The present review highlights the potential consequences of pesticide exposure on fish and humans, focusing on the (epi)genetic alterations affecting growth, behavior, and immune system. Mitigation strategies (e.g., bioremediation) to prevent/minimize the detrimental impacts of pesticides are also discussed. This review aims to shed light on the awareness in reducing the risk of water pollution for safe and sustainable pesticide management.

Genetically encoded libraries and spider venoms as emerging sources for crop protective peptides

Agricultural crops are targeted by various pathogens (fungi, bacteria, and viruses) and pests (herbivorous arthropods). Antimicrobial and insecticidal peptides are increasingly recognized as eco-friendly tools for crop protection due to their low propensity for resistance development and the fact that they are fully biodegradable. However, historical challenges have hindered their development, including poor stability, limited availability, reproducibility issues, high production costs, and unwanted toxicity. Toxicity is a primary concern because crop-protective peptides interact with various organisms of environmental and economic significance. This review focuses on the potential of genetically encoded peptide libraries like the use of two-hybrid-based methods for antimicrobial peptides identification and insecticidal spider venom peptides as two main approaches for targeting plant pathogens and pests. We discuss some key findings and challenges regarding the practical application of each strategy. We conclude that genetically encoded peptide library- and spider venom-derived crop protective peptides offer a sustainable and environmentally responsible approach for addressing modern crop protection needs in the agricultural sector.

Characterization of Neonicotinoid Metabolites by Cytochrome P450-Mediated Metabolism in Poultry

Neonicotinoids, a neuro-effective class of insecticides, are heavily applied in agricultural activities worldwide. Poultry can be exposed to neonicotinoids by several routes, but the knowledge of neonicotinoid's metabolism in poultry and its associated interspecies differences is highly limited. Hence, this study aims to investigate the species differences in metabolite formations, as well as cytochrome P450 (CYP)-dependent metabolism of four major neonicotinoid compounds, acetamiprid, imidacloprid, clothianidin, and thiamethoxam, in poultry. In vitro biotransformation assays using hepatic microsomes of chicken, ducks, geese, quails, and rats were conducted. Metabolites of neonicotinoids were then screened by LC/Q-TOF and quantified by LC/MS/MS. The results revealed an existence of interspecies differences in the formations of N-[(6-chloro-3-pyridyl) methyl] -N-methyl acetamidine (IM-1-5) of acetamiprid and dm-clothianidin of clothianidin between chicken and other species. In addition, the greatest CYP activities in the metabolism of most neonicotinoid substrates, such as acetamiprid to dm-acetamiprid, imidacloprid to hydroxylated-imidacloprid and imidacloprid-olefin, clothianidin to dm-clothianidin, and thiamethoxam to clothianidin, were found in chicken. These results suggested that the CYPs in chicken may have a greater capacity for metabolism of neonicotinoids compared to other poultry. This study further revealed that the maximum intrinsic clearance of dn-imidacloprid and dn-clothianidin in ducks may be superintended by CYP-mediated nitro-reductions of imidacloprid and clothianidin. Further studies employing CYP recombinant enzymes may be required to elucidate the specific CYP isoforms that may be involved in neonicotinoid metabolism in avian species.

Exposure to neonicotinoid pesticides induces physiological disorders and affects color performance and foraging behavior in goldfish

We investigated the effects of neonicotinoid pesticides (NEOs) on the spontaneous swimming and foraging behavior, as well as the morphological and physiological changes of goldfish. Most fish reared in thiamethoxam (THM)-sprayed rice fields showed the scales easily peeled off, and increased ascites. Some individuals showed decreased bio-defense activity and low plasma Ca2+. Similar changes were found in the exposure test to THM (1.0 and 20.0 μg/L) and dinotefuran (1.2 and 23.5 μg/L). Next, the effects of a low concentration of THM (1.0 μg/L) on the spontaneous swimming and foraging behavior of fish were examined. Fish exposed to THM for 1 week became restless and had increased the swimming performance, especially under natural light, white LED lighting and blue LED lighting. Goldfish exposed to THM had also increased intake of shiny white beads under green LED illumination. These results indicate that the exposure to NEO, even for a short period and at low levels, not only suppressed bio-defense activities and metabolic abnormalities, but also stress response, the swimming and foraging behavior of the fish are likely to be significantly suffered.

Neonicotinoid Pesticides Affect Developing Neurons in Experimental Mouse Models and in Human Induced Pluripotent Stem Cell (iPSC)-Derived Neural Cultures and Organoids

Neonicotinoids are synthetic, nicotine-derived insecticides used worldwide to protect crops and domestic animals from pest insects. The reported evidence shows that they are also able to interact with mammalian nicotine receptors (nAChRs), triggering detrimental responses in cultured neurons. Exposure to high neonicotinoid levels during the fetal period induces neurotoxicity in animal models. Considering the persistent exposure to these insecticides and the key role of nAChRs in brain development, their potential neurotoxicity on mammal central nervous system (CNS) needs further investigations. We studied here the neurodevelopmental effects of different generations of neonicotinoids on CNS cells in mouse fetal brain and primary cultures and in neuronal cells and organoids obtained from human induced pluripotent stem cells (iPSC). Neonicotinoids significantly affect neuron viability, with imidacloprid (IMI) inducing relevant alterations in synaptic protein expression, neurofilament structures, and microglia activation in vitro, and in the brain of prenatally exposed mouse fetuses. IMI induces neurotoxic effects also on developing human iPSC-derived neurons and cortical organoids. Collectively, the current findings show that neonicotinoids might induce impairment during neuro/immune-development in mouse and human CNS cells and provide new insights in the characterization of risk for the exposure to this class of pesticides.

Development and Validation of a High-Performance Liquid Chromatography Diode Array Detector Method to Measure Seven Neonicotinoids in Wheat

Neonicotinoids (NEOs), used as insecticides against aphids, whiteflies, lepidopterans, and beetles, have numerous detrimental impacts on human health, including chronic illnesses, cancer, infertility, and birth anomalies. Monitoring the residues in food products is necessary to guarantee public health and ecological balance. The present work validated a new method to measure seven neonicotinoid insecticides (acetamiprid ACT, clothianidin CLT, dinotefuran DNT, imidacloprid IMD, nitenpyram NTP, thiacloprid TCP, and thiamethoxan THT) in wheat. The analytical procedure was based on simple and fast wheat sample cleanup using solid-phase extraction (SPE) to remove interferents and enrich the NEOs, alongside the NEOs' separation and quantification by reverse-phase chromatography coupled with a diode array detector (DAD). The validation process was validated using the accuracy profile strategy, a straightforward decision tool based on the measure of the total error (bias plus standard deviation) of the method. Our results proved that, in the future, at least 95% of the results obtained with the proposed method would fall within the ±15% acceptance limits. The test's cost-effectiveness, rapidity, and simplicity suggest its use for determining the levels of acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam in routine analyses of wheat.

Preliminary Bioactivity Assessment of Myrothecium Species (Stachybotryaceae) Crude Extracts against Aedes aegypti (Diptera: Culicidae): A First Approach from This Phytopathogenic Fungi

Mosquitoes, as insect vectors, play a crucial role in transmitting viruses and parasites, leading to millions of human deaths in tropical and subtropical regions worldwide. This study aimed to evaluate the effects of ethanolic extracts of three species within the genus Myrothecium (M. roridum, M. dimerum, and M. nivale) on Aedes aegypti mosquito larvae to assess the inhibitory effect on growth and development, as well as to determine mortality. We quantify the average lethal concentrations and provide a qualitative characterization of the chemical groups responsible for their potential. Phytochemical screening revealed the presence of alkaloids, flavonoids, and terpenoids in the ethanolic extracts of the three fungal species. Tannins were found only in the extracts of M. dimerum and M. roridum. We observed a clear dependence of the effects of the crude extracts on mosquito larvae on the concentrations used and the duration of exposure. The toxic effect was observed after 48 h at a concentration of 800 ppm for both M. dimerum and M. nivale, while M. roridum showed effectiveness after 72 h. All three species within the genus Myrothecium exhibited 100% biological activity after 72 h of exposure at 600 ppm. At lower concentrations, there was moderate growth and development inhibitory activity in the insect life cycle. The study highlights the effectiveness of crude Myrothecium extracts in combating mosquito larvae, with effects becoming apparent between 48 and 72 h of exposure. This initial approach underscores the potential of the fungus's secondary metabolites for further in-depth analysis of their individual effects or synergies between them.

Decreases in the number of microglia and neural circuit dysfunction elicited by developmental exposure to neonicotinoid pesticides in mice

Neonicotinoids are insecticides widely used in the world. Although neonicotinoids are believed to be toxic only to insects, their developmental neurotoxicity in mammals is a concern. Therefore, we examined the effects of developmental exposure to neonicotinoids on immune system in the brain and post-developmental behaviors in this study. Imidacloprid or clothianidin was orally administered to dams at a dosage of 0.1 mg/kg/day from embryonic day 11 to postnatal day 21. Imidacloprid decreased sociability, and both imidacloprid and clothianidin decreased locomotor activity and induced anxiety, depression and abnormal repetitive behaviors after the developmental period. There was no change in the number of neurons in the hippocampus of mice exposed to imidacloprid. However, the number and activity of microglia during development were significantly decreased by imidacloprid exposure. Imidacloprid also induced neural circuit dysfunction in the CA1 and CA3 regions of the hippocampus during the early postnatal period. Exposure to imidacloprid suppressed the expression of csf1r during development. Collectively, these results suggest that developmental exposure to imidacloprid decreases the number and activity of microglia, which can cause neural circuit dysfunction and abnormal behaviors after the developmental period. Care must be taken to avoid exposure to neonicotinoids, especially during development.

Was the massive increase in use of teratogenic agrichemicals in western states (USA) associated with declines in wild ruminant populations between 1994 and 2013?

Population declines were documented in multiple ruminant species in Montana and surrounding states starting in 1995. While weather, food sources, and predation certainly contributed, the declines were often attributed, at least partly, to unexplained factors. Use of teratogenic agrichemicals, notably neonicotinoid insecticides, fungicides, and glyphosate-based herbicides, massively increased regionally in 1994-96. The question explored in this review is whether this vastly increased use of these teratogenic pesticides might have contributed to observed population declines. We provide references and data documenting that specific developmental malformations on vertebrates can be associated with exposure to one or more of these agrichemicals. These pesticides are known to disrupt thyroid and other hormonal functions, mitochondrial functions, and biomineralization, all of which are particularly harmful to developing fetuses. Exposures can manifest as impaired embryonic development of craniofacial features, internal and reproductive organs, and musculoskeletal/integumental systems, often resulting in reproductive failure or weakened neonates. This paper reviews: a) studies of ruminant populations in the region, especially elk and white-tailed deer, prior to and after 1994; b) published and new data on underdeveloped facial bones in regional ruminants; c) published and new data on reproductive abnormalities in live and necropsied animals before and after 1994; and d) studies documenting the effects of exposures to three of the most applied teratogenic chemicals. While answers to the question posed above are complex and insufficient evidence is available for definitive answers, this review provides ideas for further consideration.

Sex-specific transgenerational effects on murine thyroid gland imposed by ancestral exposure to neonicotinoid thiacloprid

Neonicotinoids, a relatively new widely used class of insecticide is used in agriculture to control insect populations. We examined the capacity of ancestral exposure to the neonicotinoid thiacloprid (thia) to induce transgenerational effects on thyroid tissue. Pregnant outbred Swiss female mice were exposed to thia at embryonic days E6.5 to E15.5 using 0, 0.6, and 6 mg/kg/day doses. Thyroid paraffin sections were prepared for morphology analysis. We apply ELISA method to measure T4 and TSH levels, RT-qPCR for gene expression analysis, ChIP-qPCR techniques for sperm histone H3K4me3 analysis, and immunofluorescence microscopy and western blots for protein detection. We observed an alteration in the morphology of thyroids in both males and females in the F3 generation. We observed an increase in T4 hormone in F1 females and a significant T4 level decrease in F3 males. T4 changes in F1 females were associated with a TSH increase. We found that the amount of Iodothyronine Deiodinase 1 (DIO1) (an enzyme converting T4 to T3) was decreased in both F1 and F3 generations in female thyroids. GNAS protein which is important for thyroid function has increased in female thyroids. Gene expression analysis showed that the expression of genes encoding thyroid gland development, chromatin, biosynthesis and transport factors were affected in the thyroid gland in both sexes in F1 and F3. The analysis of sperm histone H3K4me3 showed that H3K4me3 occupancy at the Dio1 locus has decreased while Thyroglobulin (Tg) and Matrix Metallopeptidase 2 (Mmp2) genes have increased H3K4me3 occupancy in the sperm of F3 mice. Besides, DNA methylation analysis of our previously published datasets showed that, in the sperm of F1 and F3 thia-derived mice, several genes related to thyroid function show consistent alterations. Our data suggest that ancestral exposure to thiacloprid affects thyroid function not only in exposed but also in indirectly exposed F3 generation.

Neonicotinoid insecticides and metabolites levels in neonatal first urine from southern China: Exploring links to preterm birth

Neonicotinoids (NEOs) have indeed become the most widely used insecticides worldwide. Concerns have been raised about their potential impact on newborns due to maternal exposure and their unique neurotoxic mode of action. However, it is still poorly understood whether in utero exposure of pregnant women to environmental NEOs and their metabolites can cause carryover effects on vulnerable newborns and subsequent health consequences. In this study, we determined the concentrations of 13 NEOs and their metabolites in the first urine collected from 92 newborns, both preterm and full-term, in southern China during 2020 and 2021. NEOs and their metabolites were identified in 91 urine samples, with over 93% of samples containing a cocktail of these compounds, confirming their maternal-fetal transfer. N-desmethyl-acetamiprid, imidaclothiz, clothianidin and flonicamid were the most commonly detected analytes, with detection frequencies of 59-87% and medians of 0.024-0.291 ng/mL in the urine. The relative abundance of imidaclothiz was significantly higher in preterm newborns, those with head circumferences below 33 cm, birth lengths less than 47 cm, and weights below 2500 g (p < 0.05). When comparing newborns in the 2nd quartile of imidaclothiz concentrations with those in the 1st quartile, we observed a significant increase in the odds of preterm outcomes in the unadjusted model (odds ratio = 3.24, 95% confidence interval = 1.02-10.3). These results suggest that exposure to elevated concentrations of imidaclothiz may be associated with preterm birth.

The potential neuroprotective of luteolin against acetamiprid-induced neurotoxicity in the rat cerebral cortex

Acetamiprid is a class of neuroactive insecticides widely used to control insect pests. The current study aimed to investigate the potential neuroprotective effects of luteolin against acetamiprid-induced neurotoxicity in the rat cerebral cortex. Four equal groups of adult male rats (10 in each): control, acetamiprid (40 mg/kg for 28 days), luteolin (50 mg/kg for 28 days), and acetamiprid+luteolin cotreatment were used. Acetamiprid was shown to alter the oxidative state by increasing oxidant levels [nitric oxide (NO) and malondialdehyde (MDA)] and decreasing antioxidants [glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase-(CAT)], with increased activity of nuclear factor erythroid 2-related factor 2-(Nrf2). Likewise, acetamiprid increases the inflammatory response, as evidenced by increased interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and nuclear factor kappa B-(NF-κB). In contrast, the treatment with luteolin brought these markers back to levels close to normal, showing that it protects neurocytes from oxidative damage and the neuroinflammation effects of acetamiprid-induced inflammation. Luteolin also demonstrated a neuroprotective role via the modulation of acetylcholinesterase (AChE) activity in the cerebral cortex tissue. Histopathology showed severe neurodegenerative changes, and apoptotic cells were seen in the acetamiprid-induced cerebral cortex layer, which was evident by increased protein expression levels of Bax and caspase-3 and decreased Bcl-2 levels. Histochemistry confirmed the neuronal degeneration, as proven by the change in neurocyte colour from brown to black when stained with a silver stain. Luteolin may have a neuroprotective effect against biochemical and histopathological changes induced by acetamiprid in the rat cerebral cortex.

Assessing the contribution of the chemical exposome to neurodegenerative disease

Over the past few decades, numerous environmental chemicals from solvents to pesticides have been suggested to be involved in the development and progression of neurodegenerative diseases. Most of the evidence has accumulated from occupational or cohort studies in humans or laboratory research in animal models, with a range of chemicals being implicated. What has been missing is a systematic approach analogous to genome-wide association studies, which have identified dozens of genes involved in Alzheimer's disease, Parkinson's disease and other neurodegenerative diseases. Fortunately, it is now possible to study hundreds to thousands of chemical features under the exposome framework. This Perspective explores how advances in mass spectrometry make it possible to generate exposomic data to complement genomic data and thereby better understand neurodegenerative diseases.

No-observed-adverse-effect-level (NOAEL) clothianidin, a neonicotinoid pesticide, impairs hippocampal memory and motor learning associated with alteration of gene expression in cerebellum

Neonicotinoid pesticides (NNs) have been associated with numerous neurobehavioral effects in rodents, raising concerns about their impact on cognitive function. Clothianidin (CLO), a type of NN, was orally administered to male mice (10 weeks old, C57BL/6N) at the no-observed-adverse-effect level (NOAEL) of 50 mg/kg/day as indicated in the pesticide risk assessment report. Behavioral tests (novel location recognition and rotarod tests) evaluated hippocampal memory and cerebellar motor learning. After each test, plasma monoamines (3-methoxytyramine, histamine, serotonin, tryptamine) were measured by LC-ESI/MS/MS (Liquid chromatography-electrospray ionization/tandem mass spectrometry), and cerebellar mRNA expression was quantified by microarray and qRT-PCR analyses. The NOAEL of CLO was found to impair hippocampal memory, leading to decreased spontaneous locomotor activity and motor function. We reported, for the first time, multiple alterations of gene expression in the cerebellum associated with motor dysfunction.

Associations between maternal serum neonicotinoid pesticide exposure during pregnancy and newborn telomere length: Effect modification by sampling season

BACKGROUND

An increasing amount of evidence suggests that telomere length (TL) at birth can predict lifespan and is associated with chronic diseases later in life, but newborn TL may be affected by environmental pollutants. Neonicotinoids (NEOs) are widely used worldwide, and despite an increasing number of studies showing that they may have adverse effects on birth in mammals and even humans, few studies have examined the effect of NEO exposure on newborn TLs.

OBJECTIVE

To investigate the effects of prenatal exposure to NEOs and the interactions between NEOs and sampling season on newborn TL.

METHODS

We conducted a prospective cohort study of 500 mother-newborn pairs from the Guangxi Zhuang Birth Cohort. Ultraperformance liquid chromatographymass spectrometry was used to detect ten NEOs in maternal serum, and fluorescence quantitative PCR was used to estimate the newborn TL. A generalized linear model (GLM) was used to evaluate the relationships between individual NEO exposures and TLs , and quantile g-computation (Qgcomp) model and Bayesian kernel machine regression (BKMR) model were used to evaluate the combined effect of mixtures of components.

RESULTS

The results of the GLM showed that compared with maternal TMX levels < LOD, maternal TMX levels < median were negatively correlated with newborn TL (-6.93%, 95% CI%: -11.92%, -1.66%), and the decrease in newborn TL was more pronounced in girls (-9.60%, 95% CI: -16.84%, -1.72%). Moreover, different kinds of maternal NEO exposure had different effects on newborn TL in different sampling seasons, and the effect was statistically significant in all seasons except in autumn. Mixed exposure analysis revealed a potential positive trend between NEOs and newborn TL, but the association was not statistically significant.

CONCLUSION

Prenatal exposure to TMX may shorten newborn TL, and this effect is more pronounced among female newborns. Furthermore, the relationship between NEO exposure and TL may be modified by the sampling season.

Non-acute exposure of neonicotinoids, health risk assessment, and evidence integration: a systematic review

Neonicotinoid pesticides are utilized against an extensive range of insects. A growing body of evidence supports that these neuro-active insecticides are classified as toxicants in invertebrates. However, there is limited published data regarding their toxicity in vertebrates and mammals. the current systematic review is focused on the up-to-date knowledge available for several neonicotinoid pesticides and their non-acute toxicity on rodents and human physiology. Oral lethal dose 50 (LD50) of seven neonicotinoids (i.e. imidacloprid, acetamiprid, clothianidin, dinotefuran, thiamethoxam, thiacloprid, and nitenpyram) was initially identified. Subsequently, a screening of the literature was conducted to collect information about non-acute exposure to these insecticides. 99 studies were included and assessed for their risk of bias and level of evidence according to the Office of Health and Translation (OHAT) framework. All the 99 included papers indicate evidence of reproductive toxicity, hepatotoxicity, nephrotoxicity, neurotoxicity, immunotoxicity, and oxidative stress induction with a high level of evidence in the health effect of rodents and a moderate level of evidence for human health. The most studied type of these insecticides among 99 papers was imidacloprid (55 papers), followed by acetamiprid (22 papers), clothianidin (21 papers), and thiacloprid (11 papers). While 10 of 99 papers assessed the relationship between clothianidin, thiamethoxam, dinotefuran, and nitenpyram, showing evidence of liver injury, dysfunctions of oxidative stress markers in the reproductive system, and intestinal toxicity. This systematic review provides a comprehensive overview of the potential risks caused by neonicotinoid insecticides to humans and rodents with salient health effects. However, further research is needed to better emphasize and understand the patho-physiological mechanisms of these insecticides, taking into account various factors that can influence their toxicity.

Pre-mating nitenpyram exposure in male mice leads to depression-like behavior in offspring by affecting tryptophan metabolism in gut microbiota

Several studies have confirmed that the health status of the paternal affects the health of the offspring, however, it remains unknown whether paternal exposure to pesticides affect the offspring health. Here, we used untargeted metabolomics and 16S rRNA sequencing technology, combined with tail suspension test and RT-qPCR to explore the effects of paternal exposure to nitenpyram on the neurotoxicity of offspring. Our results found that the paternal exposure to nitenpyram led to the offspring's depressive-like behaviors, accompanied by the reduction of tryptophan content and the disorder of microbial abundance in the gut of the offspring. Further, we determined the expression of tryptophan metabolism-related genes tryptophanase (tnaA) and tryptophan hydroxylase 1 (TpH1) in gut bacteria and colonic tissues. We found that tryptophan is metabolized to indoles rather than being absorbed into colonocytes, which coursed the reduce of tryptophan availability after nitenpyram exposure. In conclusion, our study deepens our understanding of the intergenerational toxic effects of pesticides.

Malaria transmission potential of Anopheles gambiae s.l. in indoor residual spraying areas with clothianidin 50 WG in northern Benin

The study objective was to assess the frequency of the kdr-L995F and ace-1 G280S genetic mutations in Anopheles gambiae s.l. mosquitoes and examine their ability to transmit Plasmodium falciparum in areas where indoor residual spraying (IRS) was implemented with Clothianidin 50 WG. The study was conducted in six communes in the Alibori and Donga departments of which four were IRS-treated and two were untreated and served as control. Post-IRS monthly samples of adult mosquitoes were collected in study communes using human landing catches (HLC). An. gambiae s.l. specimens were processed to detect kdr-L995F and ace-1 G280S mutations via PCR as well as Plasmodium falciparum infectivity through CSP ELISA. Our data revealed a high and similar allelic frequency for the kdr-L995F mutation in both treated and control communes (79% vs. 77%, p = 0.14) whilst allelic frequency of the ace-1 G280S mutation was lower across the study area (2-3%, p = 0.58). The sporozoite rate was 2.6% and 2.4% respectively in treated and untreated communes (p = 0.751). No association was found between Plasmodium falciparum infection in Anopheles gambiae s.l. vectors and carriage of kdr-L995F and ace-1 G280S mutations regardless of genotypes. The study findings underline the need for an integrated approach to malaria control, combining different control methods to effectively target transmission. Regular monitoring of insecticide resistance and genetic mutations is essential to guide control strategies.

The domestic chick as an animal model of autism spectrum disorder: building adaptive social perceptions through prenatally formed predispositions

Equipped with an early social predisposition immediately post-birth, humans typically form associations with mothers and other family members through exposure learning, canalized by a prenatally formed predisposition of visual preference to biological motion, face configuration, and other cues of animacy. If impaired, reduced preferences can lead to social interaction impairments such as autism spectrum disorder (ASD) via misguided canalization. Despite being taxonomically distant, domestic chicks could also follow a homologous developmental trajectory toward adaptive socialization through imprinting, which is guided via predisposed preferences similar to those of humans, thereby suggesting that chicks are a valid animal model of ASD. In addition to the phenotypic similarities in predisposition with human newborns, accumulating evidence on the responsible molecular mechanisms suggests the construct validity of the chick model. Considering the recent progress in the evo-devo studies in vertebrates, we reviewed the advantages and limitations of the chick model of developmental mental diseases in humans.

Association between maternal urinary neonicotinoid concentrations and child development in the Japan Environment and Children's Study

BACKGROUND

Recent studies have reported the effect of neonicotinoid (NEO) exposures on development in human. However, information about the risk of childhood development delays due to NEO exposures is limited.

OBJECTIVES

The study aimed to examine the association between NEO exposure and child development up to 4 years of age using data of the Japan Environment and Children's Study.

METHODS

The study employed urinary NEO and metabolite concentrations in the first and second or third trimesters; the Japanese translation of the Ages and Stages Questionnaire (third edition; J-ASQ-3) scores on developmental delay in five domains, namely communication, gross motor skills, fine motor skills, problem solving, and personal-social characteristics from 6 months to 4 years of age; and self-reported questionnaire data. The associations between urinary NEO concentrations and J-ASQ-3 results were analysed using the treed distributed lag mixture model. A total of 8538 participants were included in statistical analyses.

RESULTS

The determination rates of urinary acetamiprid-N-desmethyl (dm-ACE), clothianidin (CLO), dinotefuran (DIN) and thiamethoxam (THX) were greater than 50%. Median urinary dm-ACE, CLO, DIN and THX concentrations were 0.34, 0.14, 0.22 and 0.05 ng/ml, respectively, in samples collected during gestational weeks < 23, and 0.28, 0.12, 0.18 and 0.04 ng/ml, respectively, in those collected during gestational weeks ≥ 23. The binomial scores divided by the cut-off values of the J-ASQ were used in the treed distributed lag mixture model. The highest percentage for a domain with a value less than the cut-off value was 'problem solving' at 6 months of age among all the J-ASQ-3 scores (10.5%). There was no statistically significant association between maternal urinary dm-ACE, CLO, DIN and THX concentrations during pregnancy and the J-ASQ-3 results up to 4 years of age. Objective assessment of child development in different populations may be warranted to confirm our findings.

Association between urinary neonicotinoid insecticide levels and dyslipidemia risk: A cross-sectional study in Chinese community-dwelling elderly

Experimental evidence has demonstrated that neonicotinoids (NEOs) exposure can cause lipid accumulation and increased leptin levels. However, the relationship between NEOs exposure and dyslipidemia in humans remains unclear, and the interactive effects of NEOs and their characteristic metabolites on dyslipidemia remain unknown. We detected 14 NEOs and their metabolites in urine samples of 500 individuals (236 and 264 with and without dyslipidemia, respectively) randomly selected from the baseline of the Yinchuan community-dwelling elderly cohort (Ningxia, China). The NEOs and their metabolites were widely detected in urine (87.2-99.6 %) samples, and the median levels ranged within 0.06-0.55 μg/g creatinine. The positive associations and dose-dependent relationships of thiacloprid, imidacloprid-olefin, and imidacloprid-equivalent total with dyslipidemia were validated using restricted cubic spline analysis. Mixture models revealed a positive association between the NEOs mixture and dyslipidemia risk, with urine desnitro-imidacloprid ranked as the top contributor. The Bayesian Kernel Machine Regression models showed that the NEOs mixtures were associated with increased dyslipidemia when the chemical mixtures were ≥ 25th percentile compared to their medians, and desnitro-imidacloprid and imidacloprid-olefin were the major contributors to the combined effect. Given the widespread use of NEOs and the dyslipidemia pandemic, further investigations are urgently needed to confirm our findings and elucidate the underlying mechanisms.

Protective effect of vitamin C against thiamethoxam-induced toxicity in male rats

Background

Thiamethoxam (THM) is a neonicotinoid insecticide used to control different insect pests on fruits, vegetables, and field crops. The misuse and continuous exposure to THM cause many harmful effects on health and the reproductive system.

Aim

This work aims to investigate the efficiency of vitamin C (vit C) in reducing or eliminating the harmful effects of THM on the testes, liver, and kidney of male rats.

Methods

Forty-eight sexually mature male Wister albino rats (weight: 170-190 g; age: 10-11 weeks) were randomly allocated into six groups (8 males/group). The control group was orally given distilled water, vit C group was orally treated with 200 mg/kg b.wt of vit C, group 1/10 of THM LD50 orally treated with 156.3 mg/kg b.wt of THM, group 1/20 of THM LD50 orally treated with 78.15 mg/kg b.wt of THM, group 1/10 of THM LD50 + vit C orally treated with 156.3 mg/kg b.wt of THM + 200 mg/kg b.wt of vit C, and group 1/20 of THM LD50 + vit C orally treated with 78.15 mg/kg b.wt of THM + 200 mg/kg b.wt of vit C. All groups were treated for five days per week for a whole period of 58 days. Blood samples were collected at the end of the experiment, and serum was extracted for liver and kidney functions and antioxidant measurements. Reproductive organs (testis, epididymis, and seminal vesicles) were collected and weighed at the end of the experiment.

Results

The results showed that groups exposed to 1/10 and 1/20 of THM LD50 significantly (p < 0.05) decreased the body weight, the reproductive organ weights (testis, epididymis, and seminal vesicles), spermatid count, sperm (count and motility), and testosterone concentration with an increase in abnormalities. In addition, the groups exposed to THM showed a decrease in protein concentration, albumin, and globulin, and caused an increase in glucose concentration. The activities of alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), creatinine, urea, and malondialdehyde (MDA) were increased while caused decrease in total antioxidant capacity (TAC) due to exposure to THM. The co-administration of vit C with HM modulated the harmful effects of the insecticide on testicular, liver, and kidney parameters, which confirmed in histopathological examination of testis. Groups orally treated with vit C showed a significant increase in spermatogenesis, spermatid numbers, and the weight of seminal vesicles.

Conclusion

This study showed the importance of vit C in reducing toxic effects from exposure to THM. Accordingly, the intake of vit C by individuals who regularly handle this insecticide will be beneficial in reducing the adverse effects that may occur in the liver and kidney.

Transgenerational effects of developmental neurotoxicity induced by exposure to a no-observed-adverse-effect level (NOAEL) of neonicotinoid pesticide clothianidin

Neonicotinoid pesticides (NNs) transfer rapidly from mother to offspring, which exhibit neurobehavioral effects. However, no studies have investigated NNs' transgenerational effects. We exposed F0 generation mice (mothers) to a no-observed-adverse-effect level (NOAEL) of clothianidin (CLO) during gestation and lactation, and examined the adult neurobehavioral effects of three generations of offspring (F1, F2, F3). F1 had lower birth weight, decreased locomotor activity, and increased anxiety-like behavior. In F2, body weight was affected, and there was a decreasing trend in locomotor activity and an increasing trend in anxiety-like behavior. In F3, locomotor activity tended to increase. Thus, even when only the mothers were exposed, the effects of CLOs were still observed in F1, F2, and F3 but the effects became smaller.

Sublethal effects of thiamethoxam on immune system cells in the workers of Bombus terrestris (Hymenoptera: Apidae)

Neonicotinoids harm especially bumblebees and other species in agricultural areas all over the world. The toxic effect of thiamethoxam from the neonicotinoid group has been little studied especially on bees. This research aimed to evaluate the effects of thiamethoxam on the immune system cells of Bombus terrestris workers. Different ratios of 1/1000, 1/100 and 1/10 of the recommended maximum application dose of thiamethoxam formed the experimental groups. Ten foraging workers were used for each dose and control groups. Contamination was ensured by spraying the prepared suspensions at different ratios to the bees for 20 s at a pressure of 1 atm. The effects of thiamethoxam on the structures of immune system cells of bumblebees and the amount of these cells were investigated after 48 h of exposure. In general, anomalies such as vacuolization, cell membrane irregularities and cell shape changes were detected in prohemocyte, plasmatocyte, granulocyte, spherulocyte and oenocytoid in each dose group. Hemocyte area measurements in all groups were examined comparatively between groups. In general, granulocyte and plasmatocyte sizes were decreased, while spherulocyte and oenocytoid were increased. It was also determined that there was a significant decrease in the amount of hemocytes in the 1 mm3 hemolymph as dose increased. The results of the study revealed that sublethal doses of thiamethoxam negatively affected hemocytes and their amounts of B. terrestris workers.

Proteomic responses in the human dopaminergic LUHMES cell line to imidacloprid and its metabolites imidacloprid-olefin and desnitro-imidacloprid

Neonicotinoids (neonics) are amongst the most commonly used class of pesticides globally. In the United States, imidacloprid (IMI) is extensively used for agriculture and in other common applications such as house-hold pest control. Regular exposure to IMI, and several of its known metabolites including IMI-olefin and desnitro-imidacloprid (DN-IMI), has been shown to be harmful to many organisms including mammals, birds, and fish. Studies show that neonics bind human nicotinicacetylcholine receptors (nAChRs) and cause cellular toxicity. In the dopaminergic Lund human mesencephalic (LUHMES) cell line, IMI and other neonics (10-100 μM) have been recently shown to activate intracellular calcium signaling through nAChRs. Thus, we examined proteomic responses of LUHMES cells to a 48-h treatment with 50 μM IMI, IMI-olefin, or DN-IMI. Our findings show differential effects of these neonics on cellular protein expression. Bioinformatic analysis of significantly altered proteins indicates an effect of IMI, IMI-olefin, and DN-IMI on protein synthesis and ribosomal function. These findings suggest a role for protein synthesis and transcriptional regulation in neonic-mediated dopaminergic neurotoxicity.

Screening of Toxic Effects of Neonicotinoid Insecticides with a Focus on Acetamiprid: A Review

Recently, neonicotinoids have become the fastest-growing class of insecticides in conventional crop protection, with extensive usage against a wide range of sucking and chewing pests. Neonicotinoids are widely used due to their high toxicity to invertebrates, simplicity, flexibility with which they may be applied, and lengthy persistence, and their systemic nature ensures that they spread to all sections of the target crop. However, these properties raise the risk of environmental contaminations and potential toxicity to non-target organisms. Acetamiprid is a new generation insecticide, which is a safer alternative for controlling insect pests because of its low toxicity to honeybees. Acetamiprid is intended to target nicotinic acetylcholine receptors in insects, but its widespread usage has resulted in negative impacts on non-target animals such as mammals. This review summarizes in vivo and in vitro animal studies that investigated the toxicity of specific neonicotinoids. With summarized data, it can be presumed that certain concentrations of neonicotinoids in the reproductive system cause oxidative stress in the testis; spermatogenesis disruption; spermatozoa degradation; interruptions to endocrine function and Sertoli and Leydig cell function. In the female reproductive system, acetamiprid evokes pathomorphological alterations in follicles, along with metabolic changes in the ovaries.

Neonicotinoids and pharmaceuticals in hair of the Red fox (Vulpes vulpes) from the Cavallino-Treporti peninsula, Italy

Neonicotinoids (NEOs) and active pharmaceuticals ingredients (API) are contaminants widely diffused worldwide, causing increasing concern for potential adverse effects on wildlife. However, research on these contaminants have focused on target and non-target invertebrates, while information on potential effects in terrestrial mammals is lacking. We performed preliminary non-invasive monitoring of NEOs and API in a suburban and agricultural area using hair of the Red fox. The Red fox is a widely diffused mesopredator in Europe, and its plasticity in feeding habits makes it an excellent indicator for assessing exposure to environmental contamination. We observed the presence of NEOs in many Red fox hair samples (n = 11), including imidacloprid (IMI), acetamiprid (ACE), and clothianidin (CLO). The highest quantified concentrations were 6.4 ng g^-1 dry weight (dw), 6.7 ng g^-1 dw, and 0.9 ng g^-1 dw for IMI, ACE, and CLO, respectively. The targeted APIs included non-steroidal anti-inflammatory drugs (NSAIDs) and antidepressants. APIs were less frequently detected than NEOs, and the compounds with the highest prevalence were the NSAID ketoprofen (36%), the antidepressant sertraline (36%), and its active metabolite norsertraline (27%). The presence of human pharmaceuticals such as the NSAID ibuprofen and the antidepressants sertraline, fluoxetine, and their active metabolites norsertraline and norfluoxetine suggest environmental contamination due to untreated and partially treated wastewater discharged in surface waters and soils of the study area. The detection and quantification of ketoprofen and flunixin also suggest the possible use of contaminated manure on farmland. Findings indicate that hair may be used for monitoring environmental exposure to NEOs and provide evidence that hair is a good marker of exposure for antidepressants and certain NSAIDs, including ibuprofen, ketoprofen, and flunixin.

Induction of apoptosis, oxidative stress, hormonal, and histological alterations in the reproductive system of thiamethoxam-exposed female rats

The present study aimed to investigate the oral toxic effects of 1/10 LD50 and 1/5 LD50 of thiamethoxam (TMX), a neonicotinoid insecticide, on the reproductive system of female Wistar rats. Thirty female rats were divided into three groups and supplied orally with either; saline solution, 1/10 LD50 of TMX (156 mg/kg) or 1/5 LD50 of TMX (312 mg/kg). The daily administration was extended for 30 days. Investigating the parameters of oxidative stress, hormonal levels, histopathological alterations, and the apoptotic markers (P53, BAX, BCL-2, and caspase-3) was performed in the uterus and ovary of rats. Results showed significant changes in the body weight gain, and relative weight of the left and right ovaries and uterus. Moreover, luteinizing hormone (LH), estradiol (ED), and progesterone (PG) serum levels were not significantly altered following TMX oral administration. The level of follicle-stimulating hormone in the TMX-exposed group (156 mg/kg) was significantly increased; however, a significant decrease was observed in TMX-exposed animals (312 mg/kg). TMX induced significant oxidative stress in exposed groups by reducing the activities of superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT), and elevating malondialdehyde (MDA) levels. Following hematoxylin and eosin staining, the microscopic examination revealed deteriorated luteal cells with vacuolation in the corpus luteum, a follicle containing a degenerated oocyte and degeneration/necrosis of the circular muscle layer with a high rate of apoptotic cells in TMX-exposed animals. TMX induced transcriptional alterations in apoptosis-related genes shifting towards the activation of the intrinsic apoptotic pathway. Collectively, results suggest the toxic effect of the TMX on the reproductive health of female Wistar rats.

Developmental exposure of zebrafish to neonicotinoid pesticides: Long-term effects on neurobehavioral function

Neonicotinoid compounds are commonly used insecticides which have become increasingly used as replacements of older generations of insecticides, such as organophosphates. Given the established neurotoxicity of cholinergic toxicants, developmental neurotoxicity studies are needed to identify in vertebrate species the potential toxicity of these insecticides which act on nicotinic cholinergic receptors. Previously, developmental exposure to a neonicotinoid insecticide imidacloprid was shown to cause persisting neurobehavioral toxicity in zebrafish. The current study evaluated neurobehavioral effects of embryonic exposure to two other neonicotinoid insecticides, clothianidin (1-100 µM) and dinotefuran (1-100 µM) in zebrafish (5-120 h post-fertilization), concentrations below the threshold for increased lethality and overt dysmorphogenesis. Neurobehavioral tests were conducted at larval (6 days), adolescent (10 weeks) and adult (8 months) ages. Both compounds caused short-term behavioral effects on larval motility, although these effects were distinct from one another. At a lower concentration (1 µM) clothianidin increased dark-induced locomotor stimulation the second time the lights turned off, while a higher concentration (100 µM) reduced activity in the dark at its second presentation. By contrast, dinotefuran (10-100 µM) caused a general decrease in locomotion. Specific longer-term neurobehavioral toxicity after early developmental exposure was also seen. clothianidin (100 µM) reduced locomotor activity in the novel tank in adolescence and adulthood, as well as reduced baseline activity in the tap startle test (1-100 µM) and reduced activity early (1-10 µM) or throughout the predator avoidance test session (100 µM). In addition to locomotor effects, clothianidin altered the diving response in a dose-, age- and time-block-dependent manner (1 µM, 100 µM), causing fish to remain further away from a fast predator cue (100 µM) relative to controls. Dinotefuran produced comparatively fewer effects, increasing the diving response in adulthood (10 µM), but not adolescence, and suppressing initial locomotor activity in the predator avoidance test (1-10 µM). These data indicate that neonicotinoid insecticides may carry some of the same risks for vertebrates posed by other classes of insecticides, and that these adverse behavioral consequences of early developmental exposure are evident well into adulthood.

Neurocytotoxicity of imidacloprid- and acetamiprid-based comercial insecticides over the differentiation of SH-SY5Y neuroblastoma cells

Neonicotinoids are effective insecticides with specificity for invertebrate nicotinic acetylcholine receptors. Neonicotinoids are chemically stable and tend to remain in the environment for long so concerns about their neurotoxicity in humans do nothing but increase. Herein, we evaluated the chronic toxic effects of acetamiprid- and imidacloprid-based insecticides over the differentiation of human neuroblastoma SH-SY5Y cells, which were exposed to these insecticides at a concentration range similar to that applied to crop fields (0.01-0.5 mM). Both insecticides did not have acute cytotoxic effects in both non-differentiated and in staurosporine-differentiated SH-SY5Y cells cytotoxicity as measured by the MTT and vital-dye exclusion tests. However, after a chronic (7-day) treatment, only imidacloprid dose-dependently decreased the viability of SH-SY5Y cells (F(4,39) = 43.05, P < 0.001), largely when administered-during cell differentiation (F(4,39) = 51.86, P < 0.001). A well-defined dose-response curve was constructed for imidacloprid on day 4 (R² = 0.945, EC₅₀ = 0.14 mM). During differentiation, either imidacloprid or acetamiprid dose-dependently caused neurite branch retraction on day 3, likely because of oxidative stress, to the extent that cells turned into spheres without neurites after 7-day treatment. Despite their apparent safety, the neurodevelopmental vulnerability of SH-SY5Y neurons to the chronic exposure to imidacloprid and to a lesser extent to acetamiprid points to a neurotoxic risk for humans.